1. Field of the Invention
The present invention relates to an image forming apparatus for forming an image based on image information and particularly to an image forming apparatus capable of quickly and properly performing a jam removal processing.
2. Description of the Related Art
Sheet conveyance paths for conveying sheets for various purposes are provided, for example, in an image forming apparatus such as a copier, a facsimile machine or a printer. These sheet conveyance paths, for example, include a conveyance path for introducing a sheet from a sheet cassette for storing sheets to an image forming assembly, a conveyance path for introducing a manually inserted sheet from a manual feed tray to the image forming assembly, a conveyance path for introducing a sheet from the image forming assembly to a discharge tray via a fixing device, and a conveyance path for introducing a sheet having one side printed to the image forming assembly after the sheet is turned upside down in the case of duplex printing.
There are a great number of image forming apparatuses in which some of such sheet conveyance paths are unitized (conveyance unit) and this conveyance unit is detachably mountable into an apparatus main body. In such an image forming apparatus, a sheet jam sometimes occurs with a jammed sheet present between the detachable conveyance unit and the sheet conveyance path fixedly arranged in the apparatus main body. If a user pulls the conveyance unit out in this state, the sheet is broken and it takes time and labor to deal with a succeeding jam processing. Normally, such a jam processing procedure as not to cause this situation is prepared, but it actually frequently happens that users accidentally pull the conveyance unit without noticing such a processing.
Japanese Unexamined Patent Publication No. H08-2704 discloses an image forming apparatus constructed such that a grip used to pull the conveyance unit out cannot be held by a user unless a cover member constituting one side of a sheet conveyance path is opened, thereby prohibiting the conveyance unit from being inadvertently pulled out.
However, the method disclosed in Japanese Unexamined Patent Publication No. H08-2704 requires an electrical part such as a plunger or sensor to prohibit the grip from being held, which disadvantageously complicates the construction.